/*
 * Copyright (c) 2004-2006 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Gou Pengfei
 * Date:    May. 2011
 */

#ifndef __CPU_EDGE_BASE_BINARY_PREDICTOR_HH__
#define __CPU_EDGE_BASE_BINARY_PREDICTOR_HH__

#include "base/types.hh"
#include "base/misc.hh"
#include "config/the_isa.hh"
#include "arch/isa_traits.hh"
#include "params/DerivEdgeCPU.hh"

/**
 * This class provide some common interfaces, such as lookup,
 * update and squash, for binary predictors.
 * */
template<class Impl>
class BaseBinaryPredictor
{
  public:

    typedef TheISA::BlockID BlockID;

    enum PredictorType {
        Piecewise,
        Global,
        Local,
        Tour,
        InvalidPredictionMode
    };

    PredictorType type;

    const std::string _name;

    const std::string &name() const { return _name; }

    BaseBinaryPredictor(DerivEdgeCPUParams *params, std::string _type)
        : _name(params->name + "." + _type)
    {
        if (_type == "Piecewise") {
            type = Piecewise;
        } else if (_type == "Global") {
            type = Global;
        } else if (_type == "Local") {
            type = Local;
        } else if (_type == "Tour") {
            type = Tour;
        } else {
            type = InvalidPredictionMode;
        }
    }

    BaseBinaryPredictor()
        : _name("Unknown")
    {
        type = InvalidPredictionMode;
    }

    virtual void regStats()
    {}

    virtual ~BaseBinaryPredictor()
    {}

    virtual void reset() = 0;

    /**
     * Lookup the given block address in the branch predictor and returns
     * the prediction.
     */
    virtual bool lookup(BlockID block_id, BlockID oldest_block_id,
        Addr block_pc, ThreadID tid) = 0;   

    /**
     * Update the branch predictor with the actual result of a branch.
     */
    virtual bool update(BlockID block_id, Addr block_pc,
            ThreadID tid, bool prediction, bool mispredicted) = 0;

    /**
     * Restore the branch history on a squash.
     */
    virtual void squash(Addr block_pc, BlockID block_id, bool prediction,
            ThreadID tid) = 0;

    /**
     * Restore the branch history on a squash.
     */
    virtual void squash(BlockID block_id, ThreadID tid) = 0;

    virtual uint64_t getPathHistory(ThreadID tid)
    { 
        panic("Unimplemented function: getPathHistory()\n");
        return 0; 
    }

    virtual uint64_t getPathHistory(BlockID block_id, ThreadID tid)
    { 
        panic("Unimplemented function: getPathHistory()\n");
        return 0;
    }

    virtual uint64_t getGlobalHistory(ThreadID tid) 
    {
        panic("Unimplemented function: getGlobalHistory()\n");
        return 0;
    }

    virtual uint64_t getGlobalHistory(BlockID block_id, ThreadID tid)
    {
        panic("Unimplemented function: getGlobalHistory()\n");
        return 0;
    }
};

#endif // __CPU_EDGE_BASE_BINARY_PREDICTOR_HH__
